(page 27-02) Rudder pedals and brakes...............            

Skipping from 23-04 to section 27 allows installation of the pedals and associated plumbing without having to reach around the side skins.  This situation has occurred several times where it seems advantageous to do things out of order with the build manual and it always leaves me wondering if I'm missing something which will later bite me.  The various steps for the trial fitting and assembly are easily understandable and fun with one notable exception: maintaining the proper orientation of the parts while match-drilling the steel tubes.  The picture shows the assembly in the proper orientation which it will assume when suspended from the firewall shelf.  It's put together and drilled upside down, with the assembly resting on the bolt heads through the nylon blocks.  In that orientation, the brake pedals are supposed to be clamped so that they are vertical.  Problem is, it's hard to keep them that way while match drilling (first #30, then #12, finally 1/4 inch) through the steel tubes.  The top of the pedal on the far right ended up a bit too far aft.  I'm attempting a fix by slotting the hole with a rat-tail file, then filling in the opposite edge of the hole with weld material, thereby moving the hole circumferentially.  After being spoiled by drilling so much aluminum, drilling steel is a challenge.

[Update:  After pondering the situation, I decided to abandon the fix described above.  I ordered a new pedal and torque tube from the Mothership and, rather than match-drilling in place as described in the build manual, will do the drilling in v-blocks on the drill press.  The plan is this:  Install the new parts on the assembly as before (positioned upside down from what's shown), using the pilot holes in the pedals, mark where the holes go in the torque tube, then take the two parts to the drill press and complete the drilling.]

(page 23-04) The bigger-hammer approach...                   

s

...to aircraft construction actually works, it seems.  After all the pounding, twisting, bending and spreading in a vise, the longerons fit well.  I'm deliriously happy to be done with them.  There's still a fair amount of match drilling into them, but no more bending.

It finally occurred to me that I could store the tail cone (seen here resembling a skinny aluminum tepee) by standing it up, thereby taking up much less space.  I'll need the space for the wing build.

I've decided to skip ahead to sections 27 and 28 (brakes, rudder pedals, etc.) which should be considerably easier without the side skins installed.

(page 20-05 revisited) Landing gear service bulletin.........          

Since I've yet to acquire the finish kit, the parts I received to comply with the Main Landing Gear Service Bulletin consisted of a small additional bracket connecting the center channel to the newly beefed-up side skin (at least it'll be beefed up when I install it), skin doublers (and triplers), and some CherryMax rivets to replace the now-drilled-out LP4-3s and to install the doublers.  CherryMax rivets have approximately four times the shear strength of LP4s.

The complete kit for the service bulletin will include massively beefed-up bits which attach the landing gear to the center channel.  The end result will be a much stronger landing-gear structure, which should put an end to the wrinkled side skins which showed up on some -12s after hard landings (mostly on grass).

The yellow arrow in the picture shows the new bracket with CherryMax rivets installed.  Some builders report being able to set the stronger rivets with their existing pullers.  Not the case with me.  Neither the pneumatic nor the manual puller would work.  I therefore ordered the Cherry G27 puller (shown in the picture) which, of course, performed the task admirably.  I'm always looking for an excuse to buy a new tool.

(page 23-02) Long(eron) nightmare..............                        

All of the horror stories about bending the longerons turn out to be true.  It's the biggest PITA so far by a wide margin.  I bought Larry Buller's dies, which I think are well worth the money (somewhere in the neighborhood of $47), so I was feeling pretty confident.  Pounding the bejesus out of the aluminum as put forth in the build manual didn't strike me as a good procedure either for spreading the angle or making the lengthwise bend.

The first step, after making the initial length cut and making the various marks on the extrusion, is to spread the first foot or so of the angle to 95.4 degrees.  Most builders, it seems, are using one of the plastic angle finders sold on the aviation aisle a Lowe's.  I drew the angle on a sheet of paper, using a protractor which had, in a previous life, been used to find elevation angles for communications satellites (hence the lines drawn on it, and, yes, I'm that cheap.  I hung the protractor from a paper clip and sighted along the lines).  I then bent a small length of aluminum angle to match and used it as a template as I spread the longeron.

In order to accomplish the spreading without pounding the apex with a heavy hammer (as called out in the build manual), I decided to squeeze the angle against a large socket in a 5-inch vice.  This worked well using a 16-inch pipe as a cheater on the vice handle.  I tried using a longer piece of  3/4-inch pipe (the width of the vice jaws) as a spreader rather than the socket, but this required more force than I could muster, even with the cheater.  For the second longeron, I compromised using a longer, larger diameter deep socket as a spreader.  This was the best of the three.  After reading other blogs, I discovered that others used a version of this method.

After spreading the angle 5.4 degrees, the build manual calls for the top surface to be twisted back 2.7 degrees so that it's once again horizontal.  According to the manual, this is to be accomplished using a "metric crescent wrench."  After a long search and at great expense, I was able to acquire one of these from a mail-order outfit in Russia. ;-)  Since I'm finished twisting longerons, I'll part with it for half price.  Oregonian humor.

The bending of the longeron was accomplished using the aforementioned dies from Larry Buller (shown just to the right of the small vice in the picture).  These worked well for the bend, but I had incorrectly thought that using the dies would limit the out-of-plane bend which results from the pound-with-a-heavy-hammer method described in the manual.  This didn't happen.  I started out bending the amount required to fit the template, then rotating the angle 90 degrees in the vice and removing the unwanted bend by hand (the dies can only bend in one direction).  This reduced the original bend, so it was an iterative process: bend, rotate, bend, rotate, etc.  On the second longeron I wised up and made the bend in the desired direction a few degrees more than needed to fit the template, resulting in less unwanted out-of-plane bend to remove.  This whole process did not leave me with a warm, fuzzy feeling like some of the procedures do.

***Update*** (1-22-13)
If I had to do this again, I'd use the "Orndorff Method" where the two longerons are clamped together in a T and bent at the same time.  This prevents out-of-plane bending and apparently works well.  Search on it.

(Page 22-03) The belly of the beast......                             

The assembly of the stainless steel Firewall Bottom and Firewall Shelf held no surprises.  It was my first exposure to the much discussed and dreaded ProSeal (fuel tank sealant).  I ordered the 1 oz container from the mothership and this proved way more than enough.  Instructions are minimal, so I mixed the two parts as if it were epoxy, smeared it on the upper firewall flange, did the prescribed riveting, and all was well.  I had no idea whether the working life of the ProSeal once mixed was five minutes or five hours, but it all worked.  If I had it to do again, however, I'd do step 8 before step 3.  The F-1201L bracket must be held exactly in place with one hand (preferably with a block of wood so fingers don't get drilled) while match drilling from the opposite side of the firewall.  It would be easier without the shelf installed.

 My first attempt at making said bracket from the 3/4 by 3/4 angle resulted in a piece I scrapped for minor deviations in dimensions.  After remaking and installing it, I realized the first one would have been fine since all holes are match drilled through the firewall and tunnel rib.  No dimension for the bracket is critical.  The picture shows my tight-fit, right-angle drill attachment, which was needed for drilling into the tunnel rib.

To attach the Forward Lower Fuse Assembly to the Lower Fuse Assembly and Bottom Skin, I turned the fuselage on its side (shown).  This allowed me to hold and cleco the forward assembly without assistance from the Spousal Unit.

Next up are the dreaded longerons, which involve among other things spreading a 3/4 x 3/4 angle to 95.4 degrees.  Point four degrees?  Really?

(page 22-02 again) My 433rd favorite thing.....                    

...drilling out rivets.  Continuing the curse of this section, I fabricated the Firewall Spacers for step 12, did the match drilling for the Cowl Attach Plates, and proceeded to rivet these to the Lower Fuselage Assembly.  This involved squeezing some longish 1/8th inch rivets, which I have come to dread because it exacerbates a rotator cuff injury I've developed, probably from squeezing 1/8th inch rivets.  Turns out that the inboard two rivets are a problem.  The LP4-3 shop heads of the rivets which attach the tunnel ribs to the lower firewall make it impossible to square up the squeezer with the rivet.  I put the manufactured heads on the aft side of the firewall since I'm still not sure what will be visible from the cockpit.  After two failed attempts at squeezing two of the AN470AD4-5 rivets (followed by drilling the buggers out) I surrendered and drilled out the aforementioned LP4-3s, allowing a proper alignment of the Main Squeeze.  The squeezer must be absolutely 90 degrees to the surface of the aluminum.

The moral of this story is this:  When riveting the Tunnel Ribs to the Bottom Skin in step 6, don't rivet them to the lower firewall until after step 12.  This will completely avoid what I went through tonight.  The picture shows which rivets (two on each side) to hold off on until after step 12.

(page 22-02) One omission and one mistake....         

The omission was Van's (confirmed by them). Step 2, sentence 3 should read as follows: Machine countersink the uppermost hole in the F-1288 Cooler Stiffener and all rivet attach holes.  The mistake was all mine and had nothing to do with the omission.  After carefully doing the cutting and deburring, I countersank the hole on the wrong side.  Only cost a few bucks to order but it set the tone for much confusion to follow.  In step 3, everything after the words Tunnel Ribs should be deleted.  I wasted quite a bit of time trying to figure out how the instructions, saying to rivet nutplates to the firewall bottom, could possible make sense.  Turns out they couldn't.
Step 9 has the instructions for those nutplates in the proper sequence.  Overall, I've been quite pleased so far with the entire kit, including the build manual.  There are a few places, however, where I wish they'd let me rewrite it.  I'd do it free! 

The firewall is stainless steel and everything that I'm attaching to it is aluminum, so I was a bit concerned about dissimilar metal corrosion.  I ended up priming the entire firewall (scuff with maroon ScotchBrite, clean with acetone, spray with NAPA 7220) as well as the faces of the aluminum pieces which attach to it.  Throughout the build, I've primed all mating surfaces with self-etching primer from Lowe's, which costs about one-third what the NAPA stuff costs.  The EAA instructional videos push the NAPA primer (which is made by Martin Senor) as do the people on the forums.  I did some informal scratch tests and couldn't tell any difference.  I used the "good" stuff here since it's the foot well and parts of it could presumably be visible around carpeting.  I'm not sure what goes in there, actually.